Electronic devices such as central processing units (CPUs) generate a lot of heat during normal operation. If the heat generated by the electronic devices is not properly dissipated, it can deteriorate their operational stability and damage associated electronic devices. Thus the heat must be removed quickly and efficiently to ensure the normal operation of these electronic devices. A heat dissipation device is often attached to a top surface of a CPU, to remove heat therefrom. Gap inevitably exists between the heat dissipation device and the CPU and hence causes reduce of heat transferring efficiency from the CPU to the heat dissipation device due to bad heat-conductive property of air in the gap. To ensure intimate contact between the CPU and the heat dissipation device, a layer of thermal grease is often spread on the bottom face of the heat dissipation device to fill up the gap between the heat dissipation device and the CPU.
In early times, thermal grease with a good heat-conductive property is spread on the bottom face of the heat sink when the heat sink is finally attached to the electronic component, and therefore the total assembly time increases. In order to reduce the assembly time of a final motherboard, thermal grease is often pre-spread onto the bottom face of the heat sink before heat sinks are sold. However, the thermal grease is soft at ambient termperature and easy to be erased away. So, a protective film for protecting the thermal grease has been developed.
FIG. 4 show a conventional protective film 1 for protecting thermal grease 3 spreaded on the bottom face of a heat sink 2. The protective film 1 covers on and directly contacts with the thermal grease 3. However, since the protective film 1 is pliable and directly contacts with the thermal grease 3, the thermal grease 3 is prone to be scraped when a force is exerted on the protective film 1.